Conventionally, a spark plug has been used in an internal combustion engine. Technology, by which a resistor is provided in a through hole of an insulator so as to suppress occurrence of electromagnetic noise induced by ignition, has been proposed. Technology, by which a magnetic substance is provided in the through hole of the insulator, has also been proposed.
The fact is that enough study regarding the suppression of electromagnetic noise by both the resistor and the magnetic substance has not been made.
This disclosure discloses technology by which the occurrence of electromagnetic noise can be suppressed by a resistor and a magnetic substance.